UPDATE statistica
SET calls_pered = prd_msg,
    peredb = prd_byte,
    calls_prin = prm_msg,
    prinb = prm_byte
FROM statistica JOIN
     (SELECT
       dateadd([yy], 16, CONVERT(smalldatetime, stat_date, 11)) AS my_date,
       address_x_121,
       prd_msg,
       prd_byte,
       prm_msg,
       prm_byte
      FROM stat_kalitva2, stat_elements WHERE
      (LTRIM(stat_node) = inform))
AS
 sum_select ON (address = address_x_121) and (my_date = statistica.dbegin_stat)
GO